diff --git a/plio/io/isis_serial_number.py b/plio/io/isis_serial_number.py
index 01f8fb7d3d0b5256fea5c7c99a21e4de31fecbe6..21edbad29ccfffd081a59f04fe026c5039d7cfe5 100644
--- a/plio/io/isis_serial_number.py
+++ b/plio/io/isis_serial_number.py
@@ -1,7 +1,7 @@
 import warnings
 
 import pvl
-from pvl._collections import PVLModule
+from pvl.collections import PVLModule
 
 import plio
 from plio.data import get_data